Calandria for vacuum drying-pans and the like.



H. S. TRUSCQTT.

CALANDRIA FOR VACUUM DRYING PANS AND THE LIKE. APPLICATION FILED SEPT- s 1916.

Patented Dec, 11,1911

2 SHEETS-SHEET I.

H, S. TRUSCOTL CALANDRIA FOR VACUUM DRYING FANS AND THE LIKE.

' APPLICATION FILED SEPT. 55. I916.-

Patented Dec. 11, 1917.

2 SHEETS-SHEET 2'.

harsher.

e parents FFEGEW HAROLD SAGE TRUSGOTT, 0F MAKAVVELI, KAUAI, TERRITORY OF HAWAII.

Specification of Letters Patent.

CALANDBIA FOB, VACUUM DRYING-PANS AND THE LIKE.

Patented Dec. f1, 1917.

Application filed septemb er 5,1916. Serial No. 118,558.

To all whom z'tmay concern:

'Be it known that I, HAROLD S. TRUSCOTT, a citizen of the United States, residing at Makaweli, Kauai, Territory of Hawaii, have invented certain new and useful Improvements in Calandrias for Vacuum Drying- Pans and the like; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention has for its object to provide a calandria foruse in vacuum drying pans and the like and whichconstitutes an improvement over the usual drum type of calandria in that itwill effect a more uniform and efficient heating of the liquor and will permit of a better circulation of the liquor. Furthermore, a calandria constructed in accordance with thepresent invention will permit complete discharge of the dried liquor when the discharge gate is opened.

The foregoing results are accomplished in the preferred manner by eliminating all brackets and similar elements heretofore necessary to support the calandria and which greatly interfered with the circulation of the liquor and acted as shelves to retain some of the dried material when the discharge gate was opened. According to the present invention, the tube sheets of the calandria are extended to and supported in the walls of the. vacuum drying panand the steam connections are so made that they cannot interfere withthe circulation of the liquor. In order to permit free circulation of the liquor adjacent to the walls of'the drying pan and to uniformly heat the liquor, notwithstanding the fact that the tube sheets extend to and are supported in the walls of the para, aseries of relatively large tubes are provi ed which are positioned at the peripheral edge of the calandria and encircle the usual nest .of relatively small tubes of the calan'dria'.

The invention is illustrated in the accompanying drawings, inwhich Figure 1 is a vertical elevation of a vacuum drying pan, the lower portion of which is represented in section to show the improved calandria;

Fig. 2 is a horizontal section taken on the line 2-2 of Fig. 1; and

Fig. 3 is a vertical section of the lower portion of a multiple-efiect evaporator illus trating the applicability of the present invention to the calandrias of this type of evaporator. l a

Referringfirst to Figs. 1 and 2, it will be noted that the vacuum drying pan is denoted generally by the reference character A and is of the well-known construction. In a vacuum drying pan of'this type, it is customary to employ a calandria of the socalled drum type or a calandria of the tubesheet type. It is to the latter type of calandria that the present invention is especially applicable andfor this reason, a calandria of the tubesheet type has been illustrated in Figs. land 2.

r The calandria is denoted generally by the reference character l3 and comprises the upper and lower tube sheets 1 and 2, respectively, which are supported in the walls of the pan, as clearly shown. in the drawings. Positioned between the tube sheets 1 and 2 are the usual tubes 3 constituting the nest of relatively small tubes hereinbefore referred to. It will now be noted that no brackets or other obstructions lie in the path of the circulating liquor to interfere with its circulation. The interior of the calandria forms an inclosed' steam chamber to which the steam or other heating medium is admitted through the usual steam inlets, one of which isshown at i. p The usual drain Gmay be provided tocarry off the condensation. i i

In order to permit the circulatingliquor to rise freely in the vicinity of the walls of the pan and in. orderto better distribute the steamin the calandria, a plurality of additional tubes 8 are provided which are of greater diameter than the diameter of the usual tubes 3. As best shown in Fig. 2, these relatively large tubes 8 are arranged in a circular series about thecentral relatively small tubes 3. These large tubes 8,

when positioned at the extreme periphery circulates about the tubes 3, and, therefore,

the liquor in rising through the tubes 8 will be heated in the same manner as in rising through the tubes 3.

'In Fig. '3,a calandria is illustrated of the type usually employed in multipleeffect evaporators. The invention is applicable to this type .of calandria by positioning between the tube sheets 1" and 2, the extra landria.

In both of the calandrias shown in the drawings, steam is admitted to the interior of the calandria and the liquor circulates upwardly through the tubes3'and 8 and down through the central opening 7 in'the case of the calandria shown in Figs. 1 and 2, and upwardly through the tubes 3 and 8 and down through the central opening 7 in thecase of the calandria shown in Fig. 3. In both of thecalandrias, the relatively large tubes cause a better circulation of the liquor than has been obtained by the use of ca'landrias, as heretofore constructed. A large portion of the liquor adjacent to the casing of the evaporator or drying pan is caused to rise, due to the fact that it is effectively heated as it passes through the relatively large tubes. The provision of the relatively large-tubes obviously increases the heating surface presented to the-liquor, and these tubes positioned as they are withrespect to the-relatively small tubes efl'ect a thorough and uniform heating of the entire mass of liquor.

It is to be understood from the above, that the liquid flows upwardly through the smaller tubes and the relatively larger tubes, and thus downward through the large cen- 'ter'opening, and furthermore the particular arrangement of the. tubes induces the upward flow of the liquid, as it permits that 'portion of the liquid which is adjacent to nam s or ents atentin be obtained. m

the wall of the pan to be heated by the. heating medium and consequently to rise.

In the usual drum type of calandria, a large quantity of liquor rises slowly around the drum and in the vicinityof the evaporator walls and is not effectively heated, and furthermore as the steam connections pass through the casing walls to the drum, such connections, together with the brackets, etc. that are necessary to support the drum, act as shelvesto retain some of the dried liquor when-the discharge gate'is operiedand also interfere with the free circulation of the liquor during the drying operation. The other types of calandria's heretofore used also do not permit free circulation of the liquor and do not freely discharge the dried liquor when the discharge gate is opened. When the calandrias are constructed in accordance with the present invention, however, all of the dried liquor is discharged when the discharge gate is opened, as no brackets or other obstructions act as shelves to retain some of the dried liquor. The relatively large tubes permit the dried liquor adjacent to the casing walls to descend freely toward the-discharge gate. The above-mentioned ineffective heating of the liquor which rises around the drum when a calandria of the drum-type is employed is overcome in the present instance, as that portion of the liquor which rises in the vicinity of the easing walls is thoroughly heated, because it is made to pass through the relatively large tubes. The heat is, therefore, evenly distributedv to this portion of the rising liquor, thus making the total heating action more uniform and producing a much better circulation.

What I claim is:

l. The combination with a vacuum drying pan, of a calandria comprising spaced tube sheets having a large central passage therethrough, a plurality of tubes grouped about the passage, tubes arranged in a circular series about the first mentioned tubes in close proximity to the sides of the pan, said last mentioned tubes being large with relation to the first mentioned tubes, and means for conveying a heating medium between the tube sheets and about all of said tubes.

2. The combination with a vacuum drying pan, of a calandria comprising spaced tube sheets having a large central passage therethrough, a plurality of inclined tubes grouped about the passage, tubes arranged in a circular series about the first mentioned tubes in close proximity to the sides of the pan, said last mentioned tubes being large with relation to the first mentioned tubes, and means for conveying a heating medium between the tube sheets and about all of said tubes.

3. The combination with a vacuum drying pan having a cylindrical body portion and an inverted frusto-conical bottom with an inlet at the top and an outlet at the bottom thereof, of a calandria having a large central opening, a. nest of inclined tubes extending substantially at right angles to the bottom of the pan and having their lower ends spaced therefrom,-and a circular series of vertical tubes positioned along the peripheral edge of the calandria close to the sides of the body of the pan.

In testimony whereof I afiix my signature.

HAROLD SAGE TRUSC OTT.

117 cents each, by addressin @he afiommigsiumr of Enema Wg$9 9. 

